1. Field of the Invention
The present invention relates to a process for the encrusting, pilling and granulating of seed material.
It is known in agriculture, forestry, horticulture, as well as in ornamental planting that there can be employed seed material which is encrusted, pilled or granulated.
The definition of the terminology relating to the encrusting, pilling and granulating of seed material as is presently understood in the art is described in German Pat. No. 21 35 410. For this purpose there are utilized inorganic fillers, such as kaolin, bentonite, powdered stone, organic fillers such as peat, wood flour, straw flour, and water, or aqueous salt solutions containing water-soluble plant nutrients.
2. Discussion of the Prior Art
German Laid-Open Patent Specification No. 19 15 942 relates to an encapsulated seed grain, whose seedling grains are coated with predetermined additives. Proposed therein are unexpandable, brittle materials as the "outer shell composition". This more recent proposal has also taken another path. In essence, it utilizes no materials in the outer shell compound having any extensive plasticity and permeability to gases and liquids. Contrastingly, the permeability is adapted to be attained by means of rupturing of the brittle shell after internal expansion.
This process has not rendered obvious the novel utilization of a reversibly expandable three-layer mineral having a large crystalline surface with mutually detached crystal layers.
The Laid-Open German Patent Specification No. 22 10 330 proposes the formation of "enveloping-seedling cells" through the compression of a compound into tablets. The "cell" should be constituted of two outer layers of a particulate material of large particle size, and a central pillowing layer, referred to as the impact layer, and having a smaller particle size. The material forming the outer layers, preferably, should be constituted of vermiculite, which evidences a laminar particle configuration and which is admixed with significant quantities of non-laminar particulate organic materials so as to prevent a layering of the vermiculite during pressing. These "outer layers" should be constituted of an admixture of peat moss, wood cellulose, vermiculite, inorganic nutrients, an adhesive and a lubricant. The vermiculite should rapidly expand within the tablet "when the tablet is immersed in water, so as to achieve capillary passages through which the water will flow to the seedling from the ground, and which will rapidly soften in order to be easily penetrated by the seedling when the latter germinates". These disclosures verify that this known process employs vermiculite as an expansion agent.
The process pursuant to the present invention has improved upon this state of the art. Thus, the process utilizes vermiculite as the basic material to produce a fine-grained, reversibly expandable coating material possessing special properties which, alone or in conjunction with other materials, is used in the treatment of the seedling grains.